/*
 * Copyright (C) 2014 Jörg Prante
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.xbib.io.archive.entry;

import java.io.IOException;
import java.nio.ByteBuffer;

/**
 * An interface for encoders that do a pretty encoding of archive
 * filenames.
 *
 * <p>There are mostly two implementations, one that uses java.nio
 * {@link java.nio.charset.Charset Charset} and one implementation,
 * which copes with simple 8 bit charsets, because java-1.4 did not
 * support Cp437 in java.nio.</p>
 *
 * <p>The main reason for defining an own encoding layer comes from
 * the problems with {@link String#getBytes(String)
 * String.getBytes}, which encodes unknown characters as ASCII
 * quotation marks ('?'). Quotation marks are per definition an
 * invalid filename on some operating systems  like Windows, which
 * leads to ignored ZIP entries.</p>
 *
 * <p>All implementations should implement this interface in a
 * reentrant way.</p>
 */
public interface ArchiveEntryEncoding {
    /**
     * Check, whether the given string may be losslessly encoded using this
     * encoding.
     *
     * @param name A filename or ZIP comment.
     * @return Whether the given name may be encoded with out any losses.
     */
    boolean canEncode(String name);

    /**
     * Encode a filename or a comment to a byte array suitable for
     * storing it to a zip entry.
     *
     * <p>Examples for CP 437 (in pseudo-notation, right hand side is
     * C-style notation):</p>
     * <pre>
     *  encode("\u20AC_for_Dollar.txt") = "%U20AC_for_Dollar.txt"
     *  encode("\u00D6lf\u00E4sser.txt") = "\231lf\204sser.txt"
     * </pre>
     *
     * @param name A filename or ZIP comment.
     * @return A byte buffer with a backing array containing the
     * encoded name.  Unmappable characters or malformed
     * character sequences are mapped to a sequence of utf-16
     * words encoded in the format <code>%Uxxxx</code>.  It is
     * assumed, that the byte buffer is positioned at the
     * beginning of the encoded result, the byte buffer has a
     * backing array and the limit of the byte buffer points
     * to the end of the encoded result.
     * @throws java.io.IOException
     */
    ByteBuffer encode(String name) throws IOException;

    /**
     * @param data The byte values to decode.
     * @return The decoded string.
     * @throws java.io.IOException
     */
    String decode(byte[] data) throws IOException;
}
